The heart of a computer is a magnetic hard disk drive (HDD) which typically includes a rotating magnetic disk, a slider that has read and write heads, a suspension arm above the rotating disk and an actuator arm that swings the suspension arm to place the read and/or write heads over selected data tracks on the rotating disk. The suspension arm biases the slider into contact with the surface of the disk when the disk is not rotating but, when the disk rotates, air is swirled by the rotating disk adjacent an air bearing surface (ABS) of the slider causing the slider to ride on an air bearing a slight distance from the surface of the rotating disk. When the slider rides on the air bearing the write and read heads are employed for writing magnetic impressions to and reading magnetic signal fields from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a computer program to implement the writing and reading functions.
The volume of information processing in the information age is increasing rapidly. In particular, it is desired that HDDs be able to store more information in their limited area and volume. A technical approach to meet this desire is to increase the capacity by increasing the recording density of the HDD. To achieve higher recording density, further miniaturization of recording bits is effective, which in turn typically requires the design of smaller and smaller components. The further miniaturization of the various components, however, presents its own set of challenges and obstacles.
Narrowing the magnetic spacing is one effective method for improving the recording density of a magnetic recording device, such as a HDD. The magnetic spacing corresponds to the gap between the lowest point (farthest protruding portion at the ABS) of the magnetic head and the uppermost surface of the magnetic medium. Reducing the magnetic spacing allows the read/write elements of the magnetic head to better distinguish between the magnetic fields emanating from closely spaced regions on the magnetic medium (e.g., the magnetic disk).
A narrow magnetic spacing may be achieved with a low slider fly height, i.e., flying the slider as close to the magnetic medium as possible while avoiding contact therewith. However, with the push to decrease slider fly height, variations in said height may become increasingly problematic due to head/media intermittent contact, which may reduce reading/writing quality, result in a head crash and loss of data, etc. Accordingly, while a low slider fly height may be desirable to improve the performance of a magnetic recording device, such as a HDD, a constant slider fly height may also be desirable to ensure the consistency of said performance.
The materials and/of processes used in manufacturing a slider may affect the fly height thereof. Current manufacturing techniques often result in an undesired variation in fly height from slider to slider, leading to inconsistent reading/writing performance.